Comprehensive ambient noise analyses for seismic microzonation of sarpol-e-zahab after the Mw 7.3 2017 Iran earthquake

摘要

This study is intended to investigate ambient noise recordings in form of array and single-station measurements at Sarpol-e-zahab city after the destructive Mw = 7.3 earthquake of 12 November 2017 in Kermanshah province, Iran. The ESPAC, f-k, HVTFA, and HVSR methods are applied to analyze the ambient noise and obtain useful information on three key factors of site seismic properties, i.e. the geometry of ground layers, their mechanical characteristics and site resonance frequencies. The results of this study are presented as maps of the fundamental frequency of the ground, depth of bedrock, the thickness of top cover materials, as well as the average shear wave velocity (Vs)(700)( )and (Vs)(30) for Sarpol-e-zahab. The analyses show that the single value of (Vs)(30) does not represent seismic ground response, and the depth of competent bedrock, which dominates the low-frequency seismic response amplifications is located far beyond 30 m in this city. The most effective grade II seismic microzonation of Sarpol-e-zahab is provided by combining the results of these analyses.